Formation and characterization of crystalline iron oxide films on self-assembled organic monolayers and their in situ patterning

Abstract

Crystalline and pore-free films of α–Fe2O3 were prepared on hydrophilic self-assembled organic monolayers (DTT-SAMs) at 80 °C. Subsequently, Fe3O4 and γ–Fe2O3 films were synthesized via post annealing of as-deposited α–Fe2O3. In situ patterning of crystalline iron oxide thin layers was achieved via microcontact printing (μCP) and selective deposition. μCP was used to pattern two different surface moieties of self-assembled organic monolayers (SAMs) on Au–Cr–Si substrates. An elastomeric stamp was used to transfer either hexadecanethiol (HDT) SAMs, which are to sustain deposition of iron oxide precipitates, or hydrophilic SAMs [e.g., dithiothreitol (DTT)]. Selective deposition was realized through precipitation of iron oxide phases. Iron oxide films were deposited onto hydrophilic SAMs, but not onto HDT surfaces. Line (width of <1 μm) patterns in crystalline α–Fe2O3 thin films were obtained.